Selective electrical signaling apparatus.



L. M. POTTS. SELECTIVE ELECTRICAL SIGNALING APPARATUS. APPLICATION FILED NOV. 18. 1911. RENEWED MAY 20.1915.

1 1 5 1 ,2 1 6. Patented Aug. 24, 1915.

3 SHEETS-SHEET1.

OOOOOOOOQ L. M. POTTS.

SELECTIVE ELECTRICAL SIGNALING APPARATUS.

APPLICATION FILED NOV. 18. I9H- RENEWED MAY 20.1915.

1,151,216. Patented Aug. 24, 1915.

3 SHEETS-SHEET 2.

L. M. POTTS.

SELECTIVE ELECTRICAL SIGNALING APPARATUS.

APPLICATION FILED NOV. 18. IQIL'RENEWED MAY 20,1915.

1,151,916. Patented Aug. 24, 1915.

3 SHEETSSHEET 3- I; TAT FATE @FIQE.

LOUIS M. POTTS, F BALTIMORE, MARYLAND, ASSIGNOR To 'AUsTIn MGLANAHAN, or

' BALTIMORE, MARYLAND.

SELECTIVE ELECTRICAL SIGNALING AZE'PARATUS.

Specification of Letters Patent.

Application filed November 18,1911, Serial No. 661,185. Renewed May 20, 19 15. Sefial No. 29,432.

To all whom it may concern:

Be it known that I, LOUIS M. PoTTs, a

citizen of the United States, residing at' This invention is directed more especially to improvements in apparatus for use in those systems of selective electrlcal slgnaling wherein certain time intervals are allotted to each signal, and the signal itself characterized by combinations of electrical impulses corresponding to a given signal interval. In such systems means must be provided for determining or selecting the order of transmission of the impulses which go to form a given signal, or, in other words, the order in which the impulses shall occur ,in a given si nal interval, and means must also be provi ed for timing the duration of these signal intervals, and also the duration of the signal impulses themselves. It is also just as important to maintain between the impulses which go to form a signal and oertain elements of the receiving. apparatus a definite or fixed phase relation. It is therefore of the utmost importance in this class ofdevices that their operation shall be accurate, and when once adjusted shall not be liable to unintentional variation from this adjustment. In this connection, one of the,

most important factors to be taken into consideration is the timing mechanism. The ideal timing mechanism, in such cases, is one which does not depend for its operation upon any quantity or arrangement which is liablev to become variable after once adjusted.- It is also of prime importance in this classof devices that the apparatus be positive in its action, andas simple as possible to avoid the making of fine adjustments after the apparatus is once .const-ructed. 7 I l g The primary object of this invention is to produce an apparatus which will fulfil in practice the above requirements.

r'My present invention is operable either in sending or receiving signals, and may be used connected directly in a mam line or upon a relay circuit, and may be'iise in elther simplex or duplex operation.

In addition to the general features, above pointed out, my said invention comprises Patented Aug. 2a, 1915.

also other features hereinafter described 1 and more particularly pointed out in the ac companying claims.

. In order to more fully describe my invention, reference will be had to the accompanying drawings in which Figure 1, is a diagram showing my invention in one form as applied to direct line operation, the said diagram showing my invention also as applied to both sending and receiving'signals. Figs. 2 and 3 are diagrams to illustrate the application of my invention to line relay working, as well as duplex operation, Fig. 2 being directed more especially to the transmitting connections, while Fig. 3 shows more particularly'the receiving connections. Fig. 4, is a diagram showing the use in my invention of independent vibrating reeds or tuning forks .instead of combining these in one device, as will be later more clearly understood- Fig. 5, is a fragmentary perspective view of the keyboard and key locking mechanism. Fig. 6, is an enlarged diagrammatic view to illustrate certain features of the key locking mechanism. Fig. 7, is a detailed ani-sm of the stepby-step switching device.

front elevation of the ratchet driving mech- Figs. 8, 9 and 10 are detailed side elevations of certain of the cams of said switching device. 11, is a detailed side elevation of another one of said cams, showing a portion (if-the switch lever which operates in conjunction with this cam, and also the dashpot device for rendering the said lever slow acting in one direction. Fig..12, is a diagram showing the character of-the current on the line for two signalsmentioned in the "following description.

I shall describemy'invention first with reference to direct line transmission andv then show how it may be used on a relayed circuit.

Referring now particularly to Fig. 1, this diagram shows my improved selecting-mechanism as used both for sending and receiving, reference will first be had, however,

more particularly to the apparatus as used in sending; In the specificcase shown the signals are formed or selected in the first instance by the operation, in desired-combinations according to the code employed,

of a series of switch contacts 1; the succession or order of the signal impulses is selected by the operation in succession of a plurality of movable switch levers or contacts 2 to 9, inclusive, connected in series with contacts 1; while the actual timing of the transmission of the impulses to line is effected by the tuning fork or vibrating reed 10 which places a main line conductor 11 successively in electrical connection with the eight circuits including the switches 2 to 9, inclusive, one at a time; The actual timing of the step-by-step operation of switches 2 to 9 is also reed controlled and.

namo 12 delivers negative current to a series of fixed contacts 14, with which mo'vable contacts 1 normally engage. For each of these movable switch contacts there is also a stationary contact 15, all of which connect, in transmitting, to the positive terminal or dynamo 13. The switch 16 is for the'purpose of changing from transmitting to receiving. In transmitting, this switch occupies the full line position shown. For

' receiving, its arms are shifted to the dotted line posltions, cutting out the dynamos 12,

13 and connecting the switches 1 to the common return through conductor 17.

The number of switches 1 and circuits in which they are connected is arbitrary and may vary according to the system of signals employed. In the present case I have shown my invention as employing substantially the same system of si als as that shown and described in U. Patent No. 1,105,920, wherein there is alotted to each signal a given period which we may regard as divid into eight impulse peri s or positions. In such case I employ eight switch levers 1, and consequently eight circuits in which these switchlevers areconnected. For convenience, we shall call these eight circuits the a, b, c, d, e, f, g, and kcircuits respectively. I

The signals are formed in the present 1 case by operating the contacts '1 to send them into engagement with contacts 15, in

the desired combinations, and for this purpose I may employ any suitable permutation transmitting device either automatically or manually operated.

In the above mentioned patent, I show and describe both a manual or keyboard transmitter and an automatic transmitter, either of which may be used with my present invention. I shall assume, however, in, describing the operation of my invention that the contacts 1 are operated from a keyboard, and the keyboard transmitter which I have herein shown for this purpose may be regarded, except as to the key locking .mechanism and certain details of the mechanism for operating the starting contacts of the selector mechanism, as substantially the same as that shown and described in my said patent. I have therefore shown only so much of the keyboard as will be neces: sary to understand its operation. It should be understood, however, that my invention is operative with the keyboard as described in my said patent in its entirety, that is,

including the locking mechanism shown in said patent, and I do not wish to be understood as limiting my invention to any special combination bars 19, which, when so shifted,

send corresponding contacts 1 into engagement with corresponding contacts 15. The lateral shifting of these combination bars is effected by the upper beveled edges of the key levers engaging with cam lugs 20, arranged on the lower edges of the said ba'rs. These'lugs are disposed upon the bars 'in such combinations that the operation of a given key lever will engage a given combination of said lugs, thereby shifting a corresponding combination of said bars.

The arranging of lugs on the bottom of bars.

to thus operate them in desired combinations by a series of key levers greater in number than the bars is a well known expedient in the art and need not be here further described. 4

In the case illustrated in Fig. '1, the keyboard is also provided with a movable switch contact 23 and two relatively stationary contacts 24 and 25, connected respectively to the positive and negative sources of signal- I ing current, the movable contact 23 being normally in engagement with contact 24. In case of direct line transmission current normally passes to line through contacts 24 and '23, and the selecting mechanism is started into operation by the engagement of contact 23 wlth contact 25, thereby closing an initiating circuit hereinafter more particularly described. In case of keyboard operation, 1 contacts 23, 24 and 25 form a portion of the keyboard transmitter, and contact 23 is operated by the operation of any key of the erating this contact is shown in Fig. of

cam 27 is angularly displaced one-fortieththe accompanying drawing, and will be described in detail later, as will also the mechanism for locking the keys.

The switch levers 2 to ,9 inclusive are, in the case shown, operated by a series of cams 26 to 33 respectively, all mounted fast suitably spaced apart on a shaft indicated by the dotted line 34 (Fig. 1) journaled in any desired frame not shown. For the purpose of operation by the cams 26 to 33 the levers 2 to 9 inclusive, are made inthe form of bell crank levers, and each provided with a nose suchas 9 adapted to bear upon the periphery of its cam under tension of a suitable spring such as 9". These cams operate levers 2 to 9 inclusive, to bring their contacts successively into engagement respectively with a series of stationary contacts 35 to 42, allow them to remain thus in engagement for a predetermined interval, then separate said contacts also successively, the end of the signal period finding all said contacts open or separated. For this purpose each cam is provided with one or more peripheral notches such as 33*, the number of said notches in each case depending upon the number of signals to be transmitted on each revolution of the cam shaft. In the drawings I have shown the apparatus designed for sending four complete signals on each revolution of the cam shaft, hence all of the cams 26 to 33 are provided with four equally spaced notches. The space separating these notches is equal to the angular distance which the cams travel for each signal period, less two steps of the cam. In other Words, these openings are of such extent as to permit the nose of lever 2, or any other lever occupying the position of lever 2, as shown in Fig. 1, to drop into a notch on one step of the cam, remain therein on the next step, and to rise onto the elevated portion of the cam on the next succeeding-step, occupying in the position last named the position of nose cam 9, Fig. 1. These cams 26 to 35 inclusive, are all alike in construction, but occupy relatively difi'erent angular positions on their shaft. Assuming that the cam shaft 34 makes forty steps each revolution, cams 26 to 33 are so relatively staggered that there will be an angular displace- .ment of one-fortieth of a circumference of the cams between successive cams, that is, considering cam- 26 as the first of the serles,

of a revolution behind cam, 26; cam 28 onefortieth of a revolution behind cam 27, and

" so on, throughout the series. Thenoses'of the switch levers 2 to 9 inclusive, all occupy the same relative positions on these cams,

in the case shown all being directly beneath the axis of the cams. By this arrangement the first step of the cam shaft-brings the nose of lever 2 into engagement with the adjacent notch in cam 26. The next step of the shaft brings the nose of lever 3 into engagement with its adjacent cam notch, and so on, stepping the lever along in successive order, thereby bringingthem into engagement successively and respectively with the series of fixed contacts 35 to 42 inclusive. The contact of each switch lever remains in engagement with its fixed contact of the series 35 to 42 during two steps of the cam shaft, then breaks connection therewith. A full sized detail view of one of these cams (cam 26) is shown in Fig. 8, where 26 represents the four notches above referred to.

Positive step-by-step rotation is imparted to shaft 34 through a ratchet wheel 43, fast on shaft 34, and operated by two beveled teeth 44 and '45, made fast on opposite sides of said ratchet to a pivoted anchor 46, mounted to oscillate between the poles of two stationary electromagnets 47 and 48.

The ratchet 43 has twenty equally spaced teeth, andthe'anchor teeth 44 and 45 are offset a half ratchet tooth from being diametrically opposite (see Fig. 7, for details) so that when the anchor moves in one direction, this will rotate the ratchet a half tooth space, in the direction of the arrow, and when said anchor moves in the opposite direction, this will rotate the ratchet in the same direction another half tooth space, causing said cam shaft to rotate one-fortieth of a revolution for each oscillation of the anchor. It'will therefore be seen that this anchor and ratchet mechanism while having the appearance ofan escapement, is, in fact, not an escapement mechanism at all, but

constitutes the actual driving mechanism by which positive step-by-step rotary motion is imparted to the cam shaft.

The magnets 47 and 48 receive energizing connected to a terminal of magnet 47 the lever 51 being in permanent connection with the sourceof local current. The other terminals of magnets 47 and 48 are in permanent electrical connection with the positive local main 50. The reed 10 also controls, in

the specific case shown in Fig. l; the connecting of the a to h circuits successively to line, and for this purpose is provided witha switching device comprising the pivoted lever. 55,. stationary contact 56, and movable contact 57 mounted on, but insulated from the reed, the said reed operating lever 55 against the pull of a spring 58. The contact 57 is in permanent electrical connection with alternate switch contacts 35, 37, 39 and 41, while reed contact 56 is in permanent electrical connection with switch contacts 36, 38,

40 and 42. The lever 55 is 'in permanent connection with the main line conductor 11. The reed operated switch lever 59 and its contacts 60 and 61 form a part of an auX- iliary mechanism to be described later. i

The reed 10 is made fast 'at one end in a rigid support 62 and carries at its lowerend a weight 63. The lower end of this reed is adapted to vibrate in front of the poles of a stationary electromagnet 64, the function of which is to stop the Vibration of the reed at the end of a signal period, set it free to vibrate at the commencement of a signal period and hold it against vibration except during a signal period. The magnet in no way acts as a propelling or driving force I to operate the reed or influence the rate of its operation. The magnet 64 preferably carries on each of its pole faces fast thereto a brass plate 65, the object of which is to allow the magnet 64 to demagnetize quickly, thereby allowing the reed to start vibrating instantly that the circuit of magnet 64 is broken. In making this reed, I preferably first select a broad blade of steel sufliciently thick to have a higher natural period of vibration than that required. I then secure to one end of this blade the weight 63, by which, after proper adjustment, the vibration of the reed is brought down to the desired rate. The use of this weight increases the steadiness of the vibration and also the length of time during which the reed will vibrate when once started. The weight also provides a ready means of adjusting therate of vibration. I have found that a comparatively rough adjustment is sufficient to give accurate operation, and after once so constructed the reed requires no further adjustment, the cleaning of the contacts and their adjustment not appreciably affecting 1 the rate of vibration. I may employ in connectlon with this reed any suitable contact or switching mechanism, but the pivoted,

lever arrangement shown has many practical advantages. It is easy to adjust, remains adjusted well, and makes it necessary for the contact carried by the reed to engage but one contact for each pair of contacts operated.

The magnet64 is energized from the local mains 49'and 50, and its energizing circuit includes a contact 66 and tongue of a relay 67, a switch lever 68 similar to levers 2 to 9, and a stationary contact 69 with which lever 68 normally engages. The switch lever 68 is operated by a cam 70 fast on shaft 34. This cam 70 is a duplicate of cams 26 to 33,

but is so adjusted on the shaft that in the rear slanting edge thereof so as to rise out of the notch on the first step of the cam and thereby sever electrical connection to con tact 69.

The energizing coils of relay 67 are, in the case shown in Fig. 1, in series through a reversing switch 105 (the purpose of which will'later more fully appear) with the starting contact 23, a switch lever 71 similar to 68, and a stationary contact 72 in normal engagement with switch lever 71, the switch contact 72 being permanently electrically connected to line 11 as shown.

The lever 71 is operated to make and break connection with contact 72 by a cam 73 fast on shaft 34. This cam is also provided with four equally spaced peripheral notches, but these notches allow of no lost motion between the cam and nose of its lever 71 while said nose is in the notch, and are of such size as to permit the nose of said lever to drop into them on one step of the cam, and rise thereoutof on the next step. (See Fig. 9, for details.) This cam 73 is so set on shaft 34 that in the normal position of rest the nose of lever 71 will engage one of the notches of said cam thereby closing the energizingcircuit of relay 67 at contact 72. The relay 67 is, in the case shown, polarized and its tongue given a bias, or provided with a spring 6 a by which the said tongue will instantly return to contact 66 as soon as the energizing circuit of the relay is broken.

In Fig. 1, all the moving parts are shown in the normal position of rest. During this time the coils of relay 67, reed magnet 64 and cam operating magnet 47 all receive current continuously, negative current normally passing to line from dynamo 12, through contacts 24 and 23, coils of relay 67, switch lever-71, contact 72, on toline at wire joint 74. This normal current may just as well be positive, but we will assume in the present case that it is negative.

Now let it be assumed that some key of the keyboard is operated to send a signal. The operation of this key causes, by mechanism hereinafter described, contact 23 to break connection with contact 24 and engage contact 25. The effect of this is to send through the coils of polar relay 67 current, positive in the present case, differing in polarity from its normal current. Th1s positive current passes on to line through 'contact 72, and may serve as hereinafter described to start a similar selector at some other station. Relay 67 receiving this positive current sends its tongue out of engagemen! with contact 66. This breaks the ener: gizing circuit of the reed magnet 64 which thereby being deenergized, lets go its reed whereupon the said reed starts into free vibration. The first outward vibration of this reed from its magnet breaks the normally closed energizing circuit of magnet 47 at and 48 will become alternately energized and deenergized, imparting a rocking motion to the anchor 46, and therethrough step-bystep motion to cam shaft 34, in the direction of the arrow. The reed vibrates in this manner untilthe cam shaft has made a quarter revolution, the time allotted to each signal, when the vibration of the reed will be stopped by the energization of its magnet 64. This energization' is caused by the closing of the circuit of magnet 64 at switch contact 69 by the nose of lever 68 dropping into a notch in cam 70 just before the final swing of the reed, so as to give the magnetization of the magnet 64 time to build up sufficiently to actually stop the reed at the end of the signal period.

Directly after the tongue of relay 67 breaks engagement with contact 66 to start the selector, it immediately returns to said contact as described, so that the circuit of magnet 64 will be already partially completed at that point and ready for final completion at contact 69. The circuit of reed magnet 64, having once broken at *contact 69 on the starting of the selector, will positively be held open at this point until the proper time for closing, as the nose of lever 69 will during this interval ride upon the elevated portion of cam 70. There is therefore no possibility of this circuit becoming closed until the proper time. It will therefore be seen from this that the vibrations of the reed are entirely free, and not forced vibrations, and therefore independent of voltage or.any external propelling means. The period of the tuning fork is therefore determined solely by its mechanicalvconstruction and the materials of which it is made, and can be accurately adjusted when constructed, once for all.

On the first step of the cam shaft the circuit, including contact 23 and coils of relay 67, is disconnected from line at contact 72,

owing to the elevated portion of cam 73,

sending lever 71 out of engagement with contact 72. This circuit remains thusbroken I untilthe end of the signal period, when nose of lever 71 will drop into the next notch in its cam, closing contact at 72.

As the cam shaft 34 steps around as described, the switch levers2 to 9 inclusive, will be sent successively into engagement with their respective contacts 35 to 42 inelusive, as the nose of said levers drop successively into the notches of cams 26 to 33, each of said contacts closing as the nose of its lever drops into a notch of its cam, remaining closed during the succeeding step of the cam, and opening on-the third step. At the end of a given signal period all these contacts are open as shown. During the stepping along of the switch levers 2 to 9 as described, the switchlever 55 of the vibrating reed makes and breaks contact alternately with the contacts 56 and 57, thereby connecting the contacts 35 to 42 successively to line. Therefore, depending upon which of the contacts 1 are operated, one or more positive impulses will be sent to line following each other in the order determinedby the closing of contacts 35 to 42,- and having a duration timed by the length of the connection of these contacts to linethrough the reed operated switch 55.

Let us assume that a given signal, the let ter H, for example,-is to be transmitted, and that the key for this character operates to close contacts 1 in the b and e circuits. On the first step of the cam shaft for thissignal, a circuit is partially closed at contact 35, and the reed operated lever 55 engages contact 56, but no current passes to line through this contact at this time because the a circuit is broken at contacts 1-15, and also for the reason that contact 56 does not connect with contact 35. On the next step of the cam shaft, the b circuit is partially closed at contact 36, and is also partially closed at its contact 15, still current will not pass to line, for the reason that reed switch lever 55 is, on this step, out of engagement with contact 56. On the third step of the pulse on the seventh step of the cam shaft,

through the keyboard contacts 115 in the e circuit, contact 39, and reed contact 57 and switch lever 55.. It will be seen that the actual transmission of the impulses lags one step behind the closing of contacts 35 to'42, so that the cam operated switching device really stores up, as it were, the impulses for subsequent transmission by the reed. The current on the line as it would appear for this particular signal, transmitted byclosing the b and e circuits is represented graphically in Fig. 12 by the line wy,' the dotted line OO representing the neutral line of no current, and the solid line above and below this neutral line the positive and negative current respectively. The first positive impulse on the left is the initiating or starting impulse sent on the closure of contacts ,transmitted by the selector.

23 and 25 as fully described, while the impulses indicated 6 and e are the characteristic signal impulses.

The spaces indicated a to it between the vertical dotted lines indicate the eight impulse positions or unit impulse periods for a signal interval. In Fig. 12 .the line z w shows the current on the line if the 0 and f circuits are closed to send the signal.

Depending upon which one or combination of keyboard contacts are operated various other combinations of impulses may be transmitted to line, each such combination representing according to a desired code the signal, and each signal being characterized by the code position which the particular impulse or combination of impulses occupies in a signal period. A code based upon this principle, is fully described in U. S.

Patent No. 1,105,920, and may be used with the present apparatus, but I do not limit my invention to any special code.

The primary purpose of the starting impulse sent at the beginning of each signal is to insure the maintenance of a fixed phase relation between the vibrations of the reed and the impulses received to form the signals. The starting of the reed into vibration at the commencement of each signal from-exactly the same position of rest makes it certain that the reed will start into vibration for each signal in the same phase relation to the signal impulses which follow for that signal. In other words, the starting impulse acts to correct the phase of the timing element (the vibrating reed in this case), and as this correction takes place with each signal transmission, a constant phase relation between the received impulses and the timing element at the receiving station is insured or maintained.

It is important that after the operation of any of the contacts 1 to send a given signal, that no further operation of either the operated or any other of these contacts be permitted until the signal has been completely In the case of keyboard transrm'ssion, I effect this preferably by locking all the key levers and combination bars against operation, directly after the operation of the proper ones to send the signal, and these remain locked until the signal period has elapsed, when they become automatically released. While my selector is not limited to use with any specific form of locking mechanism, I prefer to use when employing keyboard transmission an improved mechanism which I have invented for this purpose, and which I shall now describe, reference being had to Fig. 5 in connection with Fig.1 of the drawings. This mechanism comprises in the form shown,

among other parts, a latch 75 extending entiizely across the tops of the combination bars'19 and pivoted on each side thereof in the stationary side frames 76. This latch is provided with a downwardly extending nose 7, which at times is adapted to engage with notches 78 and 79 on the upper edges'of the combination bars. There are two of these notches adjacent each other on the upper edge of each combination bar, and in the normal position of these bars all of the notches 79 he directly beneath the nose 77 of the latch. This latch is provided with an upwardly extending arm 80, which forms an armature for a stationary electromagnet 81, the said arm being normally pulled away from said magnet under tension of a spring 82 which also holds the nose of the latch 75 normally out of engagement with the notches of the combination bars. The magnet 81 receives current in a circuit extending from the positive local terminal 50 through the coils of said magnet, through switch lever 83, contact 84 to the negative main 49. The lever 83 is similar to the other cam operated switch levers and is operated by a cam 85 fast on shaft 34. This cam is provided with four equally spaced short elevations 85?, and in the stopping position of the cam, the nose of switch lei'er 83 is always on top of one of these elevations, thereby breaking the circuit of the locking magnet 81 at contact 84. Cam 85 is shown in detail in Fig. 10. Directly after the cam shaft 34 starts into rotation for the selection of any signal, the elevationon cam 85 will pass from beneath the nose of switch lever 83, thereby closing the circuit of the locking magnet at'contact 84, which circuit remains closed until the end of the quarter revolution of the cam shaft to transmit the given signal, when it will be again broken by the nose of switch lever'83 riding onto the next elevation on the cam 85. Each time the circuit of magnet 81 thus becomes closed, the said magnet attracts its armature 80 and sends the nose of latch 75 I ing a signal period. These bars while held rigidly locked in this way also prevent, during a signal period, any of the key levers 18 from being operated. For this purpose each of the combination bars carries on its bottom edge, in the spaces between the cam lugs 20,

a series of equally spaced lugs 20*, each having anedge 2O (see Fig. 6) slanting in the opposite direction from the cam edges 20 of lugs 20, so that if a bar 19 is movable at all by the engagement of a key lever with a cam face 20 this bar would move backward. The cam lugs 20 also perform'the function of locking lugs and for this reason each has also a side 20 inclined similarly to that of the lugs 20. The operation of this arrangement will be clear from Fig. 6. The solid lines represent the position of a bar19, relative to the key levers, before operation. When any bar is operated, it is shifted to the dotted line position shown. This brings the lugs on the bars into such position above the key levers as will prevent them from rising and therefore lock them against operation.

When the latch 75 releases the combination bars they return to normal under the action of the contact springs 1, or may be returned in any other desired way.

For the purpose of operating the contact 23 to start the selector into operation, on the operation of any key of the keyboard, I provide in the case shown the following mechanism (see Fig. 5). Each combination bar 19 carries on its upper edge a lug 86, all of which lugs are adapted to engage a yoke 87, straddling all of the said combination bars, and pivoted in the side frames 76 as shown.

- This yoke carries a flange 88 which engages a rod or pin 89 having an insulated end' which is adapted to engage the depending arm of a bell-crank lever 90 pivoted on a fixed support 91. Also pivoted on this support, and movable relative to the lever 90 is a lever 92,- onthe depending end of which is mounted the contact 23 insulated therefrom. The dependin arm of lever 90 is normally pulled towar the yoke 87 by spring 93, while contact 23 is normally pulled away from contact 25 and into engagement with contact 24 under tension of spring 94. Pivoted to an offset on the upper end of lever 92 is a latch 95adapted to normally engage the top of one end of the horizontal arm of lever 90. Therefore, when any of the combination bars is shifted by the operation of a key lever, a lug 86 on the operated bar or bars acts throughthe yoke- 87 and pin 89. to move the depending end of the lever 90 against the tension offspring 93 to the right. This lever acting through latch 95 rotates the lever 92 in such direction as to bring contact 23 into engagement with contact 25, and out of engagement with contact 24. Immediately after this takes place, the locking mechanism operates, and in the case shown, directly after the operation of the locking mechanism *}the contact 23 automatically returns to contact 24, breaking the circuit at contact 25. This is eflected by securing to a depending arm 96 fast on the shaft 7 5 with the armature 80 of the locking magnet, a horizontally slidable' bar 97 provided with an insulated extension 98, adapted to engage the latch 95. It will therefore be seen that when the locking magnet operates,.this will shift the bar 97 to the right, Fig. 5, thereby removing latch 95 from engagement-With lever 90 under tension of spring 99. Contact 23 will then recede from contact 25 under the action of spring 94. When the operated combination bars resume their initial positions, the lever 90 returns to normal, and likewise the latch 95. The obj ect in providing this mechanism to separate contacts 23 and 25 directly after they are closed, is to prevent the repetition of a signal if the key lever to transmit that signal is held down continuously. In cases where it is not desired to provide such means, this mechanism may obviously be omitted altogether, and the contact 23 sent into engagement with contact 25 by simply being engaged by the insulating pin 89, or in any other manner. In case the above described mechanism is provided, and it is desired to repeat a letter by holding down a key lever, this may readily be done in one way by detaching the arm 96 from the rod 97.

The switching mechanism (Fig. 1) comprising the cam 100, switch lever 101, and associated parts are for the purpose of preventingthe selector from stopping at the wrong time. For this purpose the cam 100 is provided with four groups of notches 100 (see Fig. 11) each group containing nine notches and these groups are separated by' cam lugs 100 occupying the space of one notch filled in. In each stopping position of the cam the nose of the lever 101 rests upon one of the lugs 100". This lever 101 is rendered slow acting in one direction by connecting an arm 101 thereof to a dash pot piston 101 This piston makes a close sliding fit with the bore of a cylinder 101 pivoted 0n trunnions 101 and provided with a ball valve 101 which controls a small vent 101 opening into the chamber in which the piston works. The chamber in which the ball 101 rests has a relatively wide opening at its top to atmosphere. By this arrangement the piston 101 is permitted to move into the cylinder toward the valve rapidly, but its motion in the opposite direction is retarded by the valve closing the vent 101 1 Therefore the lower end of lever 101 may recede from contact 102 quickly, but its motion toward said contact will be comparatively slow. The switch lever- 59 and contact 61 of the tuning forkor reed are a part of this mechanism, the lever 59 being electrically connected to switch lever 101 while contact 61 is electrically connected to one side of the circuit of the magnet 64. As long as cam 100 is moving rapidly, switch lever 101 cannot engage contact 102 owing to the slow action of said lever toward said 101 Would have time to engage contact 102, A

thereby completing the energizing circuit of the magnet'64'through contact 61. This energizes magnet 64 which attracts its reed 10,

the said reed acting on lever 59 to break the circuit of magnet 64 at contact 61, thus starting the reed into vibration again, which will continue to vibrate until cam shaft 34 reaches its proper stopping position, when the vibration of the reed will be automati cally stopped, as hereinbefore described. At

vsuch stopping position switch lever 101 is restored to the position shown, out of-engagement with contact 102.

As hereinafter stated my improved selecting apparatus is applicable to receiving signals as well as transmitting them, Fig. 1, showing the apparatus for both these purposes. For recording the signals either received from a distant point or from the home transmitter, I connect between con tacts 1 and switch levers 2 to 9, in each of the a to h circuits, a selecting relay 103. The purpose of these relays is to operate, in combinations corresponding to the impulses which go to make up the signals, a series of circuits, and to thereby cause suitable translating devices to record the signals. For the purpose of this description it will be assumed that this recording mechanism is substantially that of the type printing recorder shown and described in my said British patent, in which case the saidtranslating devices would be a series of electromagnets 104. These selecting relays 103 are all polarized and so wound that negative current from the home station sends all their tongues against contact stops 103*. Current in the reverse direction will therefore send their tongues against contacts 103.

In case an apparatus similar to that shown in Fig. 1 is placed at the other end of, the

that which is the equivalent of reversing said windings. I preferably do the latter as to relays 103 by connecting the tongues of these relays respectively each to a terminal of one of the magnets 104, connect all the forward contacts of said relays together and all the back contacts together, and connect these forward and back contacts respectively to two contacts of a switch 105. This arrangement effects the reversal of the tongue contacts of relays 103 which has the same effect as reversing their windings.

When the movable member of switch 105 is in the position shown, contacts 103 are the forward contacts, and the relays 103 are tongues of the operated selecting relays,

then adapted to operate by current from the l l home station. When receiving from a dis tance, switch 105 is shifted to theright. This opens the circuit of all the contacts 103 and connects all the contacts 103 for operation as forward contacts.

The terminals of magnets 104 not connected to relays 103 are all connected to a common conductor 104 leading to the positive local main 50. The arm of switch 105 which controls the connections for the contacts of relays 103 is permanently electri-' cally connected to the tongue of a relay 106, the function of which will later appear.

For the purpose of rendering the relay 67 operative either from the home or distant station, the coil terminals of this relay are connected to the reversing switch 105 in such manner that when the arms of the switch are in the position shown, the relay 67 is operative by current from its home station, and when the switch is thrown to the right, the coil connections of said relay are reversed so that it .will be operative by current from the distant station.

When any one or combination ofthe selecting relays 103 receives a signal impulse either from keyboard contacts 1, or from over the line through contacts 56 or 57 and one or more of the contacts 35 to 42, the selecting relay or relays 103 so receiving these impulses will send their tongues against their forward contacts. The engagement of their forward contacts by the however, only partially completes the circuits of the magnets 104 in circuit therewith. The circuits of these magnets are not en-. tirely or finally completed until the step of the cam shaft 34 next before the last one for a given signal period. They are then completely closed by the tongue of relay 106 energizing. its forward contact, and directly after engaging said contact the tongue of this relay recedes therefrom, again breaking the circuits of the magnets 104. The operation of this relay 106 at the proper time is controlled by a cam 107 mounted fast on shaft 34 and operating switch lever 108 at times to engage a contact 109 permanently connected to the negative local main- 49.

The cam l07 is identically the same in construction as cam 7 3, but is angularly displaced one step or a fortieth of a revolution of the shaft 34 behind the cam 73, so that on next to the last step of the said shaft for a given signal the nose of lever 108 will drop into a notch of cam 107, thereby closing the circuit through that one of the coils of relay 106 which will draw its tongue to its forward contact. On the last step of the cam 107 the nose of its lever will rise onto the elevated portion of the cam and withdraw switch lever 108 from 109, thereby breaking the circuit through the coil of relay. 106 130 above referred to. The tongue of this relay Fig. 2, shows my selecting apparatus as 106 is returned to normal, away from its operating a transmitter at one end of a ducontact, by the completion of a circuit through the coil of its top magnet 106 by the closure of contacts 110 and 111. These contacts are operated, in the case shown, by a cam 112 acting on them through a slidable pin 113. This cam may be mounted on any desired moving portion of the said printing machine started into motion directly after 'the operation of magnets 104. In the case of the printer shown in my said patent this cam may be on the reciprocating actuating bar which operates the printing striker bars. The magnets of relay 106 as will be seen from the foregoing description are connected in two separate circuits.

When the device is to be used to record signals from a distant station, the switch 16 is shifted to the dotted line position, Fig. 1, thereby cutting out the dynamos 12 and 13. In this case the initial or starting impulse coming over wire 11 branches at wire joint '7 4, traverses coils of relay 67 and contact 23, and passes to earth, causing the relay 67 to start the selector switching mechanism just as described for sending. The signal impulses then traverse the selecting relays through the reed contacts 56 and 57, and switch contacts 35 to 42 as they successively close, the signal impulses being distributed to their proper selecting relay by the switch levers 2 to 9.

While I have shown in Fig. 1 a very good combined transmitting and receiving arrangement which may be used in duplicate at the two ends of a line, I do not wish to be understood as limiting my invention to such a combined arrangement since the selector may be used simply as a transmitter, even without the recording relays 103, .or, it may be used in receiving without any transmitting arrangement directly combined therewith.

In any event when two of the selectors are employed one for sending and the other for receiving over the same line their reeds are adjusted to the same rate of vibration and when once so adjusted will remain so permanently. The two devices will therefore always operate in step.

It should be understood that I do not limit my invention to any special kind of signaling current, the double dynamo arrangement shown being but one of many ways of deriving the signaling current.

Passing now to the application of myinvention to line relay operation, reference will be had particularly to Figs. 2 and 3. In these diagrams I have indicated only such parts of the selecting mechanism and connections as are concerned directly with the operation of the line relays. The other parts and connections remain the same in both direct line and relay operation.

plex line, in which 114 indicates the line transmitting relay, and 115, the main line receiving relay balanced by an artificial line 116. In this case the initiating or starting impulse and the signal impulses transmitted by thereed-operated switch 55, energize the line transmitter 114 and cause it on receiving each such impulse to draw its tongue 117 against contact 118 connected to a pole of the source of signaling current, (dynamo 12 and 13 and thus transmit to line a corresponding impulse. The current which traverses the keyboard or primary selecting contacts 1 is therefore no longer the line signaling current proper, but a purely local current derived from the mains 4950.

The tongue of the line transmitter 114 is normally pulled against its back contact under tension of spring 119, thereby normally transmitting, in the case shown, negative current to line. In the case of a neutral line transmitting relay such as 114 the poiarity of its operating current is not to be considered. In such a case the normally closed transmitter j(keyboard) contacts 14 and 24 may be dispensed with, and all of the contacts 15 and 23 simply connected to one of the local mains. In this case, the selecting relays 103 are not polarized, as in the case of Fig. 1, but each is provided with two independent windings one in series with the contacts 1, for sending thetongues of said relays against their forward stops, and another winding for returning thev tongues to their back stops. The latter windings are all in series in a circuit leading from the positive main 50, back coils of relays 103,

back coil of relay 106, cont-acts 110,111 to the negative local main. Therefore, directly after the recording machine starts into oper-. ation contacts and 111 will close and complete the circuit through the back coils arrangement Fig. 2, is substantially as described with relation to Fig. 1, hence further description of its operation is regarded as unnecessary.

It is not essential in the transmitting arrangement Fig. 2, or in the case of v direct line operation that the home record be made through the instrumentality of the selecting relays, since the home recorder may be operated mechanically as will be clear from U. S. Patent No. 1,105,920, hereinbefore referred to, in which case the relays 103 would not be employed. Nor, indeed, is it essential in employing my invention as a transmitter that any home record at all be made.

In the receiving arrangement shown in Fig. 3, the contacts of the line relay 115 are connected respectively to the terminals 49' normal is received on line relay 115,. its

tongue engages contact 124, thereby sending a positive impulse through the coils of the selector starting relay 67 which latter then starts the reed and step-by-step switching mechanism as described with relation to Fig. 1. starts, contacts 71 and 72 open, thereby cutting the relay 67 out of circuit. The coils of relays 103, however, are connected successively in circuit with the tongue of relay 115 as the switches 2 to 9 successively close.

If the tongue of relay 115 remained against its contact 124 during the entire stepping of switches '2 to 9, all the relays 103' would receive negative current, but this would not affect them, it being assumed that they are wound for; operation by positive current only. If relay 115 receives a positive impulse, however, its tongue will go over to contact 124, thereby sending positive current to that one ofsaid relays 103 which happens to be connected through its switch (2 to 9) and switch lever 55 atthe particular instant that tongue of relay 115 engages contact 124. The relay 103- receiving this positive current will then operate as described.

Fig. 4is to illustrate the use of two tuning forks or vibrating reeds 10 and 10 instead of combining these in one device. In this double reed arrangement, the two reeds are adjusted to the same rate and their magnets connected in series as shown. The reed 10 may then control the stepping of the step-by-step switch mechanism, and the reed 10 the timing'of the actual transmission of the signals to line.

Various other modifications may be made in my invention without departing from the spirit thereof, and, without limiting myself to the specific means herein shown for car- 'rying out the same.

What I claim is: I

1. Selective electrical signaling apparatus, comprising a plurality of circuits to be selectively operated, a switch ineachof said circuits, means to operate said switches successively, a single timing element for 'controlling the operation of all said switches,

When this switching mechanism 1 and means to automatically'stop the operation of said timing element at intervals.

2. Selective electrical signaling apparatus, comprising a plurality of circuits to be selectively operated, a switch in each of said circuits, means to operate said switches successively, a single timing element comprising a freely vibrating reed for controlling'the operation of all said switches, and means to automatically stop the operation of said timing element at intervals.

3. Selective electrical signaling apparatus, comprising a plurality of circuits, a switching device connected in said circuits for selecting the order of transmission of the signal impulses, means comprising a single element having a fixed periodicity of operation to time the duration of said impulses, and means to automatically stop the operation of said timing element at intervals.

4. Selective electrical signaling apparatus, comprising a plurality of circuits, a switching device connected in said circuits for selecting the order of transmission of signal impulses, means comprising a freely vibrating reed to time the duration of said impulses, and means to automatically stop the operation of said reed at the end of each signal period.

5. Selective electrical signaling apparatus, comprising means to transmit to line a succession of electrical impulses, said means including mechanism to determine the character of each of said impulses, a series of switches to determine the succession or order of said impulses, a single element acting to time theduration of each of said impulses, and means to automatically stop the operation of said timing element at intervals.

6. Selectiveelectrical signaling apparatus, comprising means to transmit to line a succession of electrical impulses, said means including mechanism to determine the character of each of said impulses, a series of switches to determine the succession or order of said impulses, a single element comprising a freely vibrating reed to time the duration of each of said impulses, and means to automatically stop the operation of said reed at intervals.

7. Selective electrical signaling apparatus, comprising means to transmit to line a succession of electrical impulses, said means ineluding key operated'mechan'ism to determine the character of each of said impulses, a series of switches to determine the succession or order of said impulses, a single ele- 'mentacting to time the duration of each of "said impulses, and means to automatically stop the operation of said timing element at intervals.

8. Selective electrical signaling apparatus,

comprising'a series ofcircuits 'to be select ively controlled, a series of'sw1tches conin combination with a second set of switches,

one in each of said circuits, means to operate said second switches successively one at a time, a main line conductor, a switch connected. between said main line conductor and said second mentioned switches, and means comprising a vibrating reed to operate said last named switch.

10. Selective electrical signaling apparatus, comprising a group of circuits, a pair of switch contacts connected respectively in alternate circuits of said group, a circuit common to all said circuits, and a timing device comprising a single element having a fixed rate of operation and operating to connect said pair of contacts alternately to said common circuit for each signal transmission.

11. Selective electrical signaling apparatus, comprising a group of circuits, a pair of switch contacts connected respectively in alternate circuits of said group, a circuit common to all said circuits, and reed controlled means to connect said pair of contacts alternately to said common circuit for each signal transmission.

12. Selective electrical signaling apparatus, comprising a plurality of branch circuits, a main line, a switch in each of said branch circuits, a plurality of keys greater in number than said switches, permutation mechanism to form operative connection between said keys and switches, a second series of switchesone of which is connected in each of said branches, a single element controlling the operation of all said second switches to select the order of the signal impulses, and a third switch common to all said branches, and acting after each of said second named switches to connect said branches successively to the main line, the said common switch also acting to open said branch circuits in advance of either the key controlled or the order selecting switches.

13. Selective electrical signaling apparatus, comprising a. plurality of branch circuits, a main line, three switching devices in each of said branches, each having a lesser number of switches than the signals to be transmitted, a plurality of key levers, one for each signal to be transmitted, and a single timing element'common to both of the other switching devices and controlling the timing of their operation.

14. Selective electrical signaling apparatus, comprising a plurality of branch circuits, a main line, three switching devices in each of said branches, each having a lesser number of switches than the signals to be transmitted, a plurality of key levers, one for each signal to be transmitted, and a single timing element comprising a freely vibrating reed common to both of the other switching devices and controlling the timing of their operation.

15. Selective electrical signaling apparatus, comprising a set of switches, reed controlled means to operate said switches in succession, and means including one of said switches to automatically stop the operation of said reed at intervals.

16. Selective electrical signaling apparatus, comprising a set of switches, means to operate said switches in succession, means comprising a freely vibrating reed controlling the timing of the operation of said switch operating means, and means including one of said switches to automatically stop the operation of said reed at the end of each signal period.

17. Selective electrical signaling apparatus, comprisinga plurality of circuits to be selectively controlled, switch contacts connected in each of said circuits, permutation mechanism to operate said contacts in predetermined combinations, switch contacts connected in said circuits in series with said first named contacts, step-by-step operated switching mechanism to operate the second mentioned contacts in succession one at a time, a pair of switch contacts connected respectively to alternate of said successively operated contacts, timing means having an independent rate of operation, and operating said last named contacts, means governed by the rate of operation of said timing device to, operate said step-by-step switching means, and switching means also operated by said step-by-step switching mechanism to stop the operation of said timing device at the end of a given period of time.

18. Selective electrical signaling apparatus, comprising a vibratory reed, means to normally hold said reed from vibration when no signals are being transmitted, means controlling said first mentioned means to release said reed at the beginning of each signal interval, and automatic means controlling said first mentioned means to stop the motion of said reed at the end of each signal interval.

19. Selective electrical signaling apparatus, comprising a plurality of normally open ed in each of said circuits to partially complete the same, means to operate said switches in succession one at a time for each signal transmission, a freely vibrating reed controlling the timing of said switches, means to start said reed into vibration at the commencement of a signal period, and means automatically acting to stop the vibration at the end of the period covering said signal.

20. Selective electrical signaling appara tus, comprising a vibratory reed, an electromagnet arranged to stop the vibration of said reed and to release said reed to start into free vibration, an energizing circuit for said magnet, switching means in the energizing circuit of said magnet to start the said reed into operation, and switching.

means automatically operating at the end of each signal period to stop the vibration of said reed.

21. Selective electrical signaling apparatus, comprising a vibratory reed, an electromagnet arranged to stop the vibration of filing the timing of said step-by-step mechasaid reed and to release said reed to start it into free vibration, an energizing circuit for said magnet, a switch having contacts connected in said energizing circuit and adapted to break said circuit to start said reed into vibration, an operating circuit for said switch, a switch for controlling said operating circuit, a second switch in the energizing circuit of said magnet, and automatic means controlled by said reed and acting at the end of each signal period to stop the operation of said reed.

22. Selective electrical signaling apparatus, comprising a vibratory reed, an electromagnet arranged to stop the vibration of said reed and to release said reed to start into free vibration, an energizing circuit for said magnet, an electro-magnetically operated switch having contacts connected in said energizing circuit and adapted to break said circuit to start said reed into vibration, an operating circuit for said switch, a switch for controlling said operating circuit, a second switch in the energizing circuit of said reed magnet, and means set into operation by the vibration of said reed on the commencement of a signal acting to operate said second switch to keep the circuit of said reed magnet positively open for a predetermined intlerval covering the transmission of a signa 23. Selective electrical signaling apparatus, comprising a plurality of 'switches, mechanism to operate 'said switches successively, mechanism to impart positive stepby-step motion to said switch operating mechanism, a freely Vibrating reed controlnisin, and means to automatically stop the operation of said reed at the end of eac signal period.

24. Selective electrical signaling apparatus, comprising a rotatable shaft, means to impart positive step-by-step rotation to said shaft, cam mechanism operated by said 1 shaft, a plurality of switch contacts operated by said cam mechanism, a vibrating reed controlling the step by step operation of shaft, electromagnets for operating said means, a plurality of cams fast on said shaft, a plurality of switch contacts operated by said cams, a plurality of circuits each including a pair of said contacts, contacts for controlling the energization of said switch operating magnets, a freely vibrating reed controlling the opening and closing of said magnet controlling contacts, and means including one of said cam operated contacts to automatically stop the operation of said reed at intervals.

26. Selective electrical signaling appara-- tus, comprising a shaft, means positively acting to impart step-by-step rotation to said shaft, a plurality of cams fast on said shaft, a plurality of switches operated in step-by-step order by said cams on the rotation of said shaft, switch contacts for transmitting signal impulses to line, a pair of switch contacts. connected respectively to alternate contacts of said step-by-step switch, a vibratory reed operating said contacts and acting to control and. time the actual transmission of the-impulsesto line, means to start said reed, and automatically acting means, comprising a cam operated switch operated by said cam shaft, -to stop the operation of said reed at the end of a predetermined interval, and reed controlled.

tus, comprising a rotatable shaft, a ratchet fast on said shaft, a rocking member having a'cam on each side of said ratchet adapted to engage alternately the teeth of said ratchet and thereby impart positivestep-by-step rotation to 'said shaft, electromagnets for operating said rocking member, a plurality of cams fast on said shaft, a plurality of switch contacts operated in succession by certain of said earns, a plurality of circuits each including a pair of said contacts, electrical contacts for transmitting the signal impulses from said circuits to line, contacts for controlling the energization of said switch operating magnets, and a freely vibrating reed controlling the said transmit ting and magnet controlling contacts.

28. Selective electrical signaling apparatus, comprising a series of circuits to be selectively controlled, a switch in each of said circuits, signal selectingmeans to operate said switches in combinations to correspond to the respective signals, a series of switch contacts, one in each of said circuits, means to close said circuits through said contacts successively one at a time, and a selecting relay for each of said circuits, each of said relays having its coils connected in said circuits between the first mentioned switches and said series of successively operated switch contacts.

29. Selective electrical signaling apparatus. comprising a series of circuits, a series of selecting relays, one connected in each of said circuits for operation by current therein, a series of circuits including the tongue and a contact of the respective-selecting relays, translating devices operated respectively by current in said relay contact circuits, a switch common to all said last named circuits, and means automatically acting to operate said last named switch subsequently to the operation of said selecting relays to close the circuits partially completed by said selecting relays.

30. Selective electrical signaling apparatus, comprising a series of key levers, a series of slidable bars operated by said key levers, a latch for locking said bars after the operation of a key lever, means carried by said bars to lock said key levers after operation, means to operate said latch to lock and release said bars, and means controlling the operation of said latch operating means.

31. Selective electrical signaling apparatus, comprising a series of key levers, a series of slidable bars operated by said key levers, a latch acting on said bars directly for locking said bars after the operation of a key lever, means to operate said latch to lock and release said bars, and means controlling the operation of said latch operating means.

32. Selective electrical signaling apparatus, comprising a series of key levers, a series of slidable bars operated by said key levers to select the signals, a latch operating on said bars to lock them against movement after operation by one of said keys, a magnet adapted to operate said latch, an ener gizing circuit. for said magnet, and a time controlled switch operating automatically to close the circuit of said magnet after the operation of any of said keys and to break the said circuit' at the end of a signal interval.

33. Selective electrical signaling apparatus, comprising a plurality of key levers, a plurality of slidable bars operated by said key levers, each of said bars having two notches in its upper edge and all of said notches being in alinement transversely of said bars in the normal position of said bars, a pivoted latch adapted to engage the notches of both the operated and unoperated bars after the operation of any key lever,

magnet, and acting to break the circuit of said magnet at the end of a signal period.

34. Selective electrical signaling apparatus, comprising a plurality of key levers, a

plurality of slidable bars operated by said key levers, each of said key levers having two notches in its upper edge and all of said notches being in alinement transversely of said bars in the normal position of said bars, a pivoted latch adapted to engage the notches of both the operated and unoperated bars after the operation of any key lever, an-

electro-magnet bringing said latch into engagement with said notches, a spring to remove said latch from said notches when said magnet is deenergized, an energizing circuit for said magnet, a switch controlled by the operation of any of said key levers and adapted to complete the circuit of said magnet, and acting to break the circuit of said magnet at the end of a signal period, and lugs on the lower edges of said bars adapted to look all said key levers agamst operation during the signal period.

35. Selective electrical signaling apparatus, comprising a plurality of circuits, a plurality of switches, one in each of said circuits, a slidable bar for each of sa1d switches for operating the same, a plurality of key levers greater in number than sa1d bars, adapted to operate the same in combinations, mechanism adapted to look all said bars against further operation by any of said key levers during a signal transmltting period, and to release the same at the end of such period, means to operate sa1d locking mechanism, and means started into operation by the operation of any of said keys, for controlling the timing of sa1d lock operating means.

36. Selective electrical signaling apparatus, comprising a plurality of circu1ts,- a plurality of switches, one in each of sa1d circuits, a slidable bar for each of sa1d switches for operating the same, a plurality of key levers greater in number than sa1d bars, adapted to operate the same 1n comblnations, mechanism adapted to look all said bars against further operat on by any of said key levers during the slgnal transmitting period, and to release the same at the end of such period, means to operate sa1d locking mechanism, means started into operation by the operation of any of said keys for controlling the timlng of sa1d lock opcrating means, and a plurality of lugs on said bars adapted to lock said key levers against operation during a signal period.

37. Selective electrical signaling apparatus, comprising a body having a natural period of motion, means to hold said body against movement when no signals are being transmitted, means controlling said first mentioned means to release said body at the beginning of each signal interval, and automatic means controlling said first mentioned means to stop the motion of said body at the end of each signal interval.

38. Selective electrical signaling apparatus, comprising means to transmit a series of electrical impulses for the individual signals, a rotatable shaft, means to operate said shaft step-by-step, and local means started into action by the first impulse of said series and operating independently of said impulses thereafter to control said step-bystep operating means.

39. Selective electrical signaling apparatus, comprising means to transmit to line a series of electrical impulses for each of a plurality of signals, a rotatable shaft, means to operate said shaft step-by-step, local means comprising a movable body having a natural period of motion and started into action by the first impulse of said series and operating independently of said impulses thereafter to control said step-by-step operating means, and local means to automatically stop the motion of said body at the end of a signal interval.

40. Selective electrical signaling apparatus, comprising transmittingmeans, a rotatable shaft, a series of elements, means carried by said shaft to operate said elements in succession, selecting means cooperating with said elements to cause said transmitting means to transmit varying signals, and locally controlled means to impart step-bystep motion to said shaft.

41. Selective electrical signalin apparatus, comprising a transmitting switch, a rotatable shaft, a series of movable elements,

cams carried bfsaidshaft to operate said elements in succession, a keyboard cooperating with said elements to cause said transmitting switch to transmit varying. signals, and locally controlled means, including a body having a natural period of motion and adapted to impart step-by-step motion to said shaft.

42. Selective electrical signaling apparatus, comprising a series ofelements to be selectively operated, means to produce a varying series of electrical impulses, each of said impulses corresponding to a certain one of said elements to be selected, a rotatable shaft adapted to cause said impulses to control the operation of corresponding elements of said series, and means locally controlled to impart step -by-step motion to said shaft.

43. Selective electrical signaling apparatus, comprising a series of elements to be operated selectively, means to produce a series of electrical impulses corresponding to certain of said elements, local means comprising a single element controlled by the first impulse of said series and independent of them thereafter, to control step-by-step the action of said impulses to actuate said elements selectively.

'44. Selective electrical signaling apparatus in which combinations of electrical impulses are transmitted for individual signals, and having means for determining the succession of the impulsesfor the respective signals, said means comprising a plurality of movable members, a rotatable shaft, means operated by said shaft to opcrate said members in succession, means to rotate said shaft step-by-step, and local means started into action by the first impulse for each signal and operating independently thereafter to control said step by-step operating means.

45. Selective electrical signaling apparatus in which combinations of electrical impulses are transmitted for individual signals, comprising a plurality of movable members, a rotatable shaft, means operated by said shaft to operate said members in succession, mechanism including a toothed Wheel and a movable anchor acting thereon, to impel step-by-step rotation of said shaft, a body having a natural period of motion and operatively connected to said step-b-y-step impelling mechanism to time its operation, and means controlled by the first impulse for each signal to start said body into motion, the said body operating thereafter during the interval of the signal to independently control the rotation of said shaft.

46. Selective electrical signaling apparatus in which combinations of electrical impulses aretransmitted for individual signals, comprising a plurality of movable members, a rotatable shaft, cams operated by said shaft to operate said members in succession, mechanism including a toothed Wheel and a movable anchor acting thereon, to impel step-by-step rotation of said shaft, 2. body having a natural period of motion, a magnet energized by a starting impulse accompanying each signal, means controlled by said magnet when so energized to start said body into motion, the said body acting thereafter during the signal interval to independently control said step-by-step impelling mechanism.

47. Selective signaling apparatus compris ing in combination with means to produce a series of electrical impulse-s, a series of elements to be operated selectively and corresponding to certain of said impulses, local means comprising a single element 'controlled by the first impulse of said series and independent of succeeding impulses of said series, to control step-by-step the action of said elements selectively.

48. Selective signaling apparatus comprising in combination with means to produce a series of electrical impulses, a series of elements selectively controlled by certain of the impulses of said series, local means comprising a single element controlled by the first impulse of said series and independent of the succeeding impulses thereof, to control step-by-step the selective action of said impulses on said elements.

49. Selective electrical signalingapparw, tus in which the time intervals allotted individual signals are divided into equal im-' pulse periods which are combined to form the signals, a series of movable selector elements, a rotatable shaft, means operable by said shaft to operate said elements in successive order corresponding to said impulse periods of a signal interval, means including a toothed wheel and a movable anchor acting thereon, to impel step-by-step motion of said shaft, a body having a natural period of motion, local to said step by-step impelling means and operatively connected thereto to time its motion, and means operatively associated with said body to correct the phase thereof with respectto the signal impulses.

50. Selective electrical signaling apparatus in which the time intervals allotted individual signals are divided into equal im pulse periods which are combined to form the signals, a series of movable selector ele ments, a rotatable shaft, means operable by said shaft to operate said elements in suc-- cesslve order corresponding to sa1d impulse periods of a signal interval, mechanism including a toothed wheel and a movable an-.

pulse periods which are combined to form' the signals,'a series of electrical contacts, a rotatable shaft, means operable by said shaft to close said contacts in successive order corresponding to said impulse periods of a signal interval, means including a* toothed wheel and a movable anchor acting thereon,to impel step-by-step motion of said shaft, a body having a natural period of motion, local to said step-by-step impelling means and operatively connected thereto to timeits motion, and means operatively as sociated with said body to correct the phase 7 thereof with respect to the signal impulses. In testimony whereof I affix my signature in presence of two witnesses.

Louis ro'r'rs. Y Witnesses: I

HYMAN I. ROBINSON,

HARRY N. RODENMAYER. 

